8-hydroxyquinoline-2-carboxylic acid as possible molybdophore: A multi-technique approach to define its chemical speciation, coordination and sequestering ability in aqueous solution

Alberto Pettignano, Salvatore Cataldo, Gabriele Lando, Francesco Crea, Francesco Cacciola, Winfried Plass, Katia Arena, Demetrio Milea, Silvio Sammartano, Luigi Mondello, Concetta De Stefano, Giuseppe Brancato, Sofia Gama

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Abstract

8-hydroxyquinoline-2-carboxylic acid (8-HQA) has been found in high concentrations (0.5–5.0 mmol·dm−3) in the gut of Noctuid larvae (and in a few other lepidopterans), in which it is proposed to act as a siderophore. Since it is known that many natural siderophores are also involved in the uptake and metabolism of other essential elements than iron, this study reports some results on the investigation of 8-HQA interactions with molybdate (MoO42−, i.e., the main molybdenum form in aqueous environments), in order to understand the possible role of this ligand as molybdophore. A multi-technique approach has been adopted, in order to derive a comprehensive set of information necessary to assess the chemical speciation of the 8-HQA/MoO42− system, as well as the coordination behavior and the sequestering ability of 8-HQA towards molybdate. Chemical speciation studies have been performed in KCl(aq) at I = 0.2 mol·dm−3 and T = 298.15 K by ISE-H+ (glass electrode) potentiometric and UV/Vis spectrophotometric titrations. CV (Cyclic Voltammetry), DP-ASV (Differential Pulse-Anodic Stripping Voltammetry), ESI-MS experiments and quantum mechanical calculations have been also performed to derive information about the nature and possible structure of species formed. These results are also compared with those reported for the 8-HQA/Fe3+ system in terms of chemical speciation and sequestering ability of 8HQA.
Original languageEnglish
Pages (from-to)1-21
Number of pages21
JournalBiomolecules
Volume10
Publication statusPublished - 2020

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology

Cite this

Pettignano, A., Cataldo, S., Lando, G., Crea, F., Cacciola, F., Plass, W., Arena, K., Milea, D., Sammartano, S., Mondello, L., De Stefano, C., Brancato, G., & Gama, S. (2020). 8-hydroxyquinoline-2-carboxylic acid as possible molybdophore: A multi-technique approach to define its chemical speciation, coordination and sequestering ability in aqueous solution. Biomolecules, 10, 1-21.